


The Strange Case of Dr. Stark and Mr. Hyde

by switchknitter



Category: Marvel Cinematic Universe, The Avengers (Marvel Movies)
Genre: Alternative Universe - Jekyll and Hyde Fusion, Happy Ending, M/M, Pining
Language: English
Status: Completed
Published: 2019-04-28
Updated: 2019-04-28
Packaged: 2020-02-09 08:18:37
Rating: Mature
Warnings: Creator Chose Not To Use Archive Warnings
Chapters: 2
Words: 2,719
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/18634342
Author URL: https://archiveofourown.org/users/switchknitter/pseuds/switchknitter
Summary: The year is 1886.  Dr. Tony Stark, scientist and Avenger, is missing.  A killer is loose in New York, and it's up to Thor's exiled brother Loki to find Stark before he is found dead -- or worse.A Jekyll and Hyde fusion, but with sentiment.





	1. Chapter 1

**Author's Note:**

> This plot bunny grabbed me out of nowhere. Enjoy!

_1886_

“Brother. I need your help.” Thor was making that face, the puppy dog one that irked Loki to no end even as he agreed to whatever Thor wanted.

It was a Saturday night in February, and Loki was already in his pajamas and dressing gown. All he’d wanted to do was sit in the front of the fireplace and read a spellbook he’d picked up on Vanaheim earlier in the day. But now here was Thor, ruining his peace. “What is it now, Thor?”

“Tony Stark is missing.”

Damn. Thor had figured out some time ago that Loki had _feelings_ for Stark, so of course Thor would use that against him. “He’s probably out with some trollop. It _is_ Saturday night.” Loki tried to hide the bitterness in his voice. He failed, given the pity in Thor’s eyes.

Loki sighed and changed clothes with a thought: his favorite black suit, green cravat, black greatcoat, black gloves. He pulled his hair into a queue and picked up his silk top hat from the rack behind the door. “Where was he last seen?”

“At home. A window was left open, though. I thought you could follow his trail, or something.”

“I am a mage, not a bloodhound,” Loki snapped.

Thor looked slightly cowed. “Sorry, brother.”

Loki sighed. “I have a… tracer, of sorts… on Stark. I will find him.” He shut and locked the door to his upscale brownstone, and then closed his eyes to focus on Stark. He could sense the mortal, though nothing about his well-being. “I can find him. I will meet you back at his home.”

“Thank you, Loki. It will mean the world to the Avengers.”

“I care not for your Avengers, and you know it.” Loki tipped his hat to his brother mockingly and disappeared.

He reappeared to find a monstrous, deformed creature attacking a man. Loki at first assumed the man was Stark, but no, Stark was the beast! Horror filled Loki. What had been done to his mortal?

Quickly, Loki cast a sleep spell on Stark and checked on his victim. The poor soul was dead of… fire damage? Stark felt hot to the touch as well. What had happened to Stark, to cause such changes?

Loki lifted Stark over his shoulder and skywalked them to Stark’s home. He thanked the Norns that he could travel so, and did not have to haul the oversized creature through the streets of New York. There would be too many questions.

At Stark’s mansion, Loki laid Stark on his bed, cast a bright mage light, and looked the mortal over. His face was misshapen and burnt. His shoulders and limbs were unevenly sized. The only ways he knew it was Stark were by the tracer, and by the pinky ring Stark wore -- the mark of an Avenger, cutting deep into a finger hideously swollen.

There were no traces of magic on Stark, besides the one Loki had put there. Whatever had happened to him, this was no curse.

Loki heard Thor coming up the stairs, eternally able to recognize his brother’s tread. “Did you find him?”

“I did.” Loki gestured to the still form on the bed.

Thor gasped. “It is the Beast!”

“It is Tony Stark,” Loki corrected, annoyed.

“It cannot be. This monster has killed half a dozen people over the last two weeks. We’ve been tracking him!” Thor was telling the truth.

“Was Stark helping you find him?”

“No… Stark has been… unwell.”

“Obviously,” Loki replied, gesturing to Stark. “He keeps journals, does he not?”

“Yes,” Thor replied, eyes still on Stark. “Somewhere.”

Loki sighed. “Must I do everything for you?” He left the bedroom, in search of Stark’s laboratory. There, buried under a haphazard pile of equipment, he found notes on a serum called Extremis. Stark had been taking it in hopes of prolonging his life. (He was dying? How had Loki not known?) Apparently he had only recently grown aware of the consequences, and was trying to reverse it. His handwritten notes had a feverish quality to them, as if Stark was desperate and out of time.

Returning to the bedroom, Loki found the other Avengers had gathered in his absence. Loki didn’t like them. While he might no longer be a villain, he still detested their self-righteousness. So he didn’t bother with greetings. “Stark has taken a drug to heal himself of some illness. It seems to have had unintended consequences.”

The Avengers all began talking at once, much to his annoyance, so he shut them up with a spell. “Yes, I am sure this is he. I may be able to reverse it with magic, but I cannot say for sure.”

The Captain of America raised his hand, and Loki gave him back his voice. “Do you know what disease ails him, that he would resort to this?”

“I do not know. When I restore him to himself, I will ask him. And heal him, in return for a boon.” Loki was lying, he would heal Stark anyway, but it never hurt to have heroes in his debt. “Now leave. All of you. I have work to do.” He returned their voices as they reluctantly left. “Thor, you keep watch. I must not be interrupted.”

“Aye, brother.” Thor closed the door behind him, and Loki pulled a chair up next to the sleeping Stark.

Work to do, indeed.

\---

Some hours later, near dawn, Loki emerged from Stark’s bedroom, exhausted. The Avengers were all hovering in the hallway. Fools.

“How is he?” Banner asked.

“He is well, though he will sleep most of the day. The thing in his chest was poisoning him. I removed it, and all traces of Extremis.”

“You removed the arc reactor?” the Captain exclaimed. “But he needs it to be Iron Man!”

“That is not my problem,” Loki replied. “He would have died if I left it alone. I would think you’d prefer a live friend than a dead hero.”

There was no arguing with that, so Loki bid them goodbye and returned home. As tired as he was, he kept wondering if he would have discovered Stark’s ailment in time if Stark hadn’t taken Extremis. It was unlikely, and the idea of a universe without Stark in it depressed him terribly. Loki couldn’t bring himself to feel bad about Stark’s victims, not when they led him to saving the man himself. Most mortals meant nothing to Loki; he was dutifully serving out his exile from Asgard, but he kept himself apart from the humans. There was no point in getting attached when they would die so quickly.

But Stark… Stark shone so very brightly. And now he would live nearly as long as Loki. After he’d rid Stark of Extremis, he’d given him one of the golden apples he kept hidden away in case of emergency. Stark might be displeased, but Loki couldn’t bring himself to care. An angry Stark might forgive him one day. A dead one never would.

When Loki finally slept, he was troubled by dreams of Stark’s monstrous form attacking him, cursing him, telling him he was worthless and could never mean anything to Stark. He rose late in the afternoon, to the sensation of his wards being disturbed.

He threw on his dressing gown and rushed downstairs. Stark was banging on the door. “Odinson! I know you’re in there! Let me in!”

Loki opened the door and hauled the man inside by one arm. “There is no need to disturb the whole neighborhood,” he hissed, shutting the door with his free hand.

Stark’s eyes were wild. He looked some twenty years younger, but he was… afraid? “What have you done to me?”

Loki merely raised an eyebrow. “You were dying, Mr. Stark. What should I have done?”

Stark scowled, looking like he wished to punch Loki. “After what I did to all those people? You should have shot me, not healed me.”

Ah. Guilt. A silly sentiment. But Loki knew saying as much would infuriate Stark even more. Instead, he chose his words carefully. “I felt your worth as a hero to this realm outweighed your crimes, especially since you were not in your right mind at the time.” He paused. “If you wish, I can construct a corpse of your Extremis self. You can show it to the authorities, let them believe you took care of the problem yourself.”

“That’s not the point, Odinson.” 

Norns, Loki hated that all the humans went by their last names in this time and place. As if Loki enjoyed the reminder of his father every time anyone spoke to him. 

Stark continued ranting, unaware of Loki’s irritation. “I was the one who killed those people. Seven dead, by my hand!”

“As I said, you were not in your right mind. And I doubt you expected your serum to turn you into a murderer.”

Stark began to pace. “I should have tested it more thoroughly.”

“You were running out of time. I saw the poison in your blood.”

“For god’s sake, stop being so understanding!”

“Why, when you would obviously prefer to castigate yourself for the rest of eternity?” Loki smirked. “You made a mistake, borne from desperation. I do not blame you, and I doubt your friends do either.”

Stark stopped pacing, but the scowl didn’t leave his face. “I want to be angry with you.”

Loki shook his head. “You’re angry with yourself and wish to take it out on me. There is a difference.”

“Dammit.” All the fight went out of Stark, and he slumped against the wall. “We’re not friends. How do you know me so well?”

Stark couldn’t know how much that stung. “We may not be friends,” Loki told him, “but we have much in common.”

“We do?” Stark looked disbelieving.

Loki half-shrugged. “I am not the villain you think I am,” he murmured.

“I know that Asgard cast you out for attacking Earth. I know you did not cause harm of your own volition, but neither have you shown remorse.”

“I cannot bring back the dead, no matter how much guilt I may feel,” Loki replied, looking away. He didn’t need Stark knowing that he _did_ feel remorse. It made Loki feel weak. He hadn’t felt guilt, originally, but being forced to live here among the humans had made him all too aware of how fragile they were. Which was Odin’s reason for the exile, he supposed. The old bastard was far too canny for Loki’s liking.

Stark blinked in astonishment. “You do care about us humans.”

“Tell anyone and I’ll murder you in your sleep.”

Stark just laughed at the threat. “No you won’t. Not after you put all that work into healing me.”

Loki rolled his eyes. Great, now Stark would be insufferable. (Loki ignored the part of him that was pleased with their banter. At a thousand years old his heart should _not_ be fluttering like a teenage boy’s.) “I can always change my mind.”

Grinning, Stark nudged Loki with his shoulder. “You like me.”

Taken aback, Loki blushed. And to compound the problem, Stark _saw_.

“Oh,” Stark said wonderingly. “You actually… oh.”

“You may leave now, Stark,” Loki hissed, feeling frozen in place.

“I… um… all right. I’ll go.” The man opened the door.

“Speak of this to anyone, and I will end you.” Loki didn’t mean it, but he needed Stark to believe he did.

“I swear to you, no one else will know. I promise.” And with that, Stark was gone.


	2. Chapter 2

Thor would have said Loki was brooding. Thor wouldn’t have been wrong.

Loki spent the next two days shut up in his townhouse, avoiding everyone and everything. Unfortunately he couldn’t escape his own thoughts, even with a bottle of elven wine he had tucked away. The brew just made him more morose.

On the morning of the third day, Stark once again disrupted the wards by knocking on Loki’s door.

Loki opened the door wearily. “What now?”

Stark seemed uncharacteristically tense. “Can I come in?”

Loki made no reply, only opened the door further. He closed it behind Stark, and waited.

“I… have dinner with me.” Stark was tense, and it made Loki even moreso.

“I do not wish for your pity,” Loki informed him stonily. “Nor will I let you escape your debt so easily by flattery alone.”

“No, no! You misunderstand,” Stark said, his eyes… pleading? Surely Loki was reading that wrong. “You said we had much in common. I would like to know you better.”

“Why?” Loki bit out.

Stark sighed, softened. “I have always found you… attractive, but cold. Reserved. I enjoy the company of men as well as women, but I never thought you’d be…”

“Sentimental?” Loki sneered, trying to hide his surprise at this new turn of events.

“Something like that, yes,” Stark said, undeterred. “The other day I was so shocked by the notion you might care for me that I left without giving you a word of encouragement. Well. Here I am, to repair any damage I did to your esteem.” Stark clasped his hands behind his back and waited for Loki’s reply.

Loki was shaken. As the God of Lies, he knew when someone was trying to fool him. Stark was sincere, but Loki had to be sure. “You would court me, then? Court a monster?”

“You have seen my dark side made flesh, and still you desire me. Cannot that hold true for us both?”

Well then. Loki crowded Stark against the wall, pinning him in place. “You may regret your decision, Stark.”

“As may you,” Stark replied, breathless at having Loki pressed against him. “And my name is Tony.”

Loki brought his mouth down on Tony’s, and oh, reaching Valhalla could have felt no sweeter. Tony let him take everything he wanted, and more. Pulling back just enough to lean his forehead against Tony’s, he said, “My name is Loki. You will be screaming it soon enough.”

Tony laughed, and it was a wicked thing. “You will have to earn that pleasure, _Loki_.”

They barely made it to the bedroom, Loki half-dragging Tony up the stairs between kisses. He pushed Tony down on the coverlet and took Tony’s clothes from him with a thought.

“I could learn to love magic,” Tony laughed, pulling Loki down atop him.

_You could learn to love_ ** _me_** , Loki thought, but instead focused on discovering what made Tony moan and cry out for more.

Once their passion had been sated twice over, Tony melted into the mattress and sighed happily. “However you healed me, you’ve given me more stamina than I had at half my age.”

“Ah. About that.” Loki winced, feeling his happy afterglow fade away too quickly. “I… may have made you a little bit immortal.”

“You… I beg your pardon, but I don’t think I heard that right.”

Loki’s shoulders slumped. “The idea of a future without you in it seemed… bleak. I understand if you’re angry.”

Tony closed his eyes. He was silent for a long time, long enough that Loki wondered if the man had fallen asleep. But then he looked at Loki, face grave. “You really are in love with me.”

Loki cringed and nodded wordlessly.

“I cannot say I feel the same, yet the possibility exists that I may someday love you in return. But -- and it’s a rather important question -- what will you do if things don’t work out the way you want them to?”

Loki shrugged, not looking at Tony. “Then I will go on, as I always have, alone. But even so, I still believe the future will benefit from you in it.”

Then Tony’s warm hand was on Loki’s arm, pulling him towards Tony none too gently. Once they were laying face to face, Tony kissed him softly. “Then thank you, for this gift. As a man of science I must admit the idea of seeing eternity pleases me greatly. I hope you never regret giving it to me.”

“I won’t,” Loki swore. “I never could.”

Tony’s brilliant smile made every hardship Loki had ever gone through seem less painful, if it had all been leading up to this. “Now kiss me again, Loki. I want to see if I can make you scream _my_ name this time.”

And Loki did.


End file.
